Modem engine technology, including diesel technology, is being held to increasingly strict emissions standards, as the Environmental Protection Agency (E.P.A.) introduces its Tier 2 regulations in an effort to curb automotive pollution. For example, new emissions standards set by the E.P.A. and scheduled to phase in from 2004 to 2009 require substantial reductions in emissions of particulate matter, nitrogen oxides and sulfur from diesel engines.
The E.P.A. has proposed a cap of 15 parts per million (ppm) of sulfur in diesel fuel beginning in 2006. Currently, the cap is set at 500 ppm. This has led to a new class of ultra-low-sulfur diesel (ULSD) fuels with levels of 50 ppm sulfur or less. ULSD fuel has been proposed as a technology enabler to pave the way for advanced, sulfur-intolerant exhaust emission control technologies; however, ULSD fuel is not without drawbacks.
First, ULSD fuel is produced through additional hydroprocessing and higher-severity hydrotreating of fuel. These processes reduce sulfur levels; however, in doing so, they adversely affect beneficial fuel properties. For example, the removal of sulfur- and hydrocarbon-based polar molecules during hydroprocessing may rob the fuel of the natural lubricity provided by these compounds. Low-lubricity fuels can result in premature wear and failure of fuel system components.
Additionally, severely hydrotreated fuels may be depleted of natural antioxidants that help prevent the fuel from forming gums and sludges. Furthermore, ULSD fuel can be more corrosive than conventional fuels.
Many chemical fuel additives have been developed to counteract the above-mentioned negative aspects of ULSD fuel. For example, a consumer may purchase fuel additive de-icers and depressants, as well as fuel additives designed to lubricate, clean, regulate viscosity and boost cetane levels. These additives may extend the life and enhance the performance of a diesel engine, and may further reduce emissions, thus aiding drivers in meeting increasingly stringent E.P.A. emission standards. However, for the average driver, conventional methods of including such fuel additives in a fuel tank are messy, inconvenient, time-consuming and potentially hazardous.
Currently, fuel additives are either introduced into bulk storage tanks from which fleet vehicles are fueled, or poured directly into vehicle fuel tanks from consumer-oriented packages (i.e., cans, bottles and the like). Most of the supplemental additives used in diesel fuel do not have a residual affect and must be supplied to each tank of fuel, especially chemicals such as flow improvers and deicers used in cold weather. Furthermore, fuel additives are commercially available in particular package sizes that are not necessarily the correct dose for each and every diesel vehicle.
Thus, the operator of a passenger or larger diesel vehicle that is not fueled from a bulk tank must often carry containers of fuel additive inside their vehicles and must treat every tank of fuel piped into the vehicle. Introducing a fuel additive into the fuel tank takes time, as the operator must locate the container of additive, calculate the amount of additive required for the vehicle in question, and then feed the additive into the tank. Furthermore, a funnel is usually required to feed fuel additives into a fuel tank. Both the funnel and the fuel additive containers can drip dangerous chemicals onto the hands, body or clothing of the vehicle's operator. Funnels and additive containers can also leak dangerous chemicals and fumes inside the vehicle. This causes problems even when the operator stores the additive containers in a trunk of the vehicle, as any leakage can damage other goods stored in the trunk. However, storing additives inside the vehicle may be particularly hazardous when the vehicle in question is an SUV or a van lacking a trunk or outside storage area. The operator of such a vehicle essentially rides with the chemicals and/or fumes in the passenger compartment, which may or may not be sufficiently ventilated to disperse chemical fumes into the outside air.
Hence, there remains a need for a fuel additive storage system that is contained outside of the passenger compartment, that is convenient to operate and that supplies an optimal amount of fuel additive in a proper dosage for a specific vehicle.